The words “ויחד יתרו" that the Pasuk uses, meaning ‘Yisro rejoiced’, also comes from the word ‘Echad’ - as in ‘Yisro UNIFIED’ G-d, by realizing that all other forces are really just creations of the One and ONLY true G-d.
Why do the words ‘rejoiced’ and ‘unified’ share the same root?
When a person believes in many gods, then the problems of life all seem to come from many forces. The lack of rain is because the rain god is angry, and the problems with the wife are because the god of love is conspiring against you, and the lack of income is because the god of sustenance is upset, etc. But when a person recognizes that all the forces of the world, both the good and the bad, all come from one just and loving G-d, who sees to it that everyone gets what’s coming to them (like what happened with the Egyptians), it brings a person to true joy! When we realize that even the 'perceived' bad is really from the ONE loving G-d who has only ONE goal, to bestow good on His creations, then we can be sure that what feels hard and painful is really only for our benefit. This knowledge is the key to achieving true joy and inner peace.
When we are pulled to look at things we shouldn’t or towards forbidden desires, what is really happening deep down in our hearts is that we are believing in other gods (or godessess?) who we think can provide our needs OTHER than Hashem.
The Zohar states that when Rabbi Shimon Bar Yochai would pass by beautiful women with his students, he would urge them to avert their eyes and would recite the Pasuk “אל תפנו אל האלילים – do not turn to other gods.” When we look where we shouldn’t, in our subconscious minds we are denying that Hashem is the ONLY provider or our needs, and we are giving strength in our minds to those ‘goddesses’ out there, who we perceive as beings who can ‘provide our needs’. This is the root of all idol worship, the idea that some other force or being in nature is a provider that is separate from G-d.
There is nothing wrong with recognizing that there are indeed other forces and providers in nature. We find this many times in the Torah as described above (Yisro exclaimed that G-d is greater than all other gods, and Yaakov called Eisav’s angel a god, and G-d Himself declares he has allotted the other gods to the nations, etc.). The problem begins however, when we perceive these forces as separate from G-d Almighty. It takes Emunah to internalize that all forces and providers are only creations of G-d, and it is HE Who provides all our needs!
The Pasuk at the end of Yisro says:
וַיֹּאמֶר ה' אֶל-מֹשֶׁה, כֹּה תֹאמַר אֶל-בְּנֵי יִשְׂרָאֵל: אַתֶּם רְאִיתֶם--כִּי מִן-הַשָּׁמַיִם, דִּבַּרְתִּי עִמָּכֶם.
לֹא תַעֲשׂוּן, אִתִּי: אֱלֹהֵי כֶסֶף וֵאלֹהֵי זָהָב, לֹא תַעֲשׂוּ לָכֶם.
And the LORD said unto Moses: Thus thou shalt say unto the children of Israel: Ye yourselves have seen that I have talked with you from heaven.Ye shall not make with Me--gods of silver, or gods of gold, ye shall not make unto you.
How many of us are guilty of making money (silver and gold) into a god? We run after it and worship it as if ithe 'money' provides our needs. But all the money of the world is G-d's, as the the Pasuk in Chagai (2:8) says: לי הכסף ולי הזהב. It is G-d who created all the forces and effects that seem to provide and create...
So if G-d exhorts us to stay away from forbidden pleasures, then how can we give strength in our minds to these mere creations, if the One who created them and truly provides for all tells us it isn’t good for us! Believing that there is “good” to be had from a “provider” that is OTHER than Hashem is a form of idol worship.